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1.
Biosensors based on carbon nanotubes 总被引:6,自引:0,他引:6
Carbon nanotubes (CNTs) exhibit a unique combination of excellent mechanical, electrical and electrochemical properties, which has stimulated increasing interest in the application of CNTs as components in (bio)sensors. This review highlights various design methodologies for CNT-based biosensors and their employment for the detection of a number of biomolecules. In addition, recent developments in the fields of CNT-based chemiresistors and chemically sensitive field-effect transistors are presented. After a critical discussion of the factors that currently limit the practical use of CNT-based biosensors, the review concludes with an outline of potential future applications for CNTs in biology and medicine.
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2.
Alain Walcarius 《Analytical and bioanalytical chemistry》2010,396(1):261-272
Nano- and/or macrostructuring of electrode surfaces has recently emerged as a powerful method of improving the performances
of electrochemical devices by enhancing both molecular accessibility and rapid mass transport via diffusion, by increasing
the electroactive surface area in comparison to the geometric one, and/or by providing confinement platforms for hosting suitable
reagents. This brief overview highlights how template technology offers advantages in terms of designing new types of porous
electrodes—mostly based on thin films, and functionalized or not—and discusses their use in analytical chemistry via some
recent examples from the literature on electrochemical sensors and biosensors.
相似文献
3.
Wang L Fine D Sharma D Torsi L Dodabalapur A 《Analytical and bioanalytical chemistry》2006,384(2):310-321
This article reviews recently published work concerning improved understanding of, and advancements in, organic and polymer
semiconductor vapor-phase chemical sensing. Thin-film transistor sensors ranging in size from hundreds of microns down to
a few nanometers are discussed, with comparisons made of sensing responses recorded at these different channel-length scales.
The vapor-sensing behavior of nanoscale organic transistors is different from that of large-scale devices, because electrical
transport in a nanoscale organic thin-film transistor depends on its morphological structure and interface properties (for
example injection barrier) which could be modulated by delivery of analyte. Materials used in nanoscale devices, for example
nanoparticles, nanotubes, and nanowires, are also briefly summarized in an attempt to introduce other relevant nano-transducers.
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4.
Thin nanoporous alumina obtained by anodization of aluminum films offers promising advantages for application in fluorescence-based biological sensors including convenient preparation, increased density of binding sites, and improved collection efficiency of fluorescence. These advantages are illustrated in the detection of streptavidin using biotin covalently bound to the surface of alumina nanopores. Fluorescence intensity enhancement as high as 7 times is observed in nanopores in comparison to flat glass surface.
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5.
Ma X Zhu T Xu H Li G Zheng J Liu A Zhang J Du H 《Analytical and bioanalytical chemistry》2008,390(4):1133-1137
A chemical prototype sensor was constructed based on nanofiber-structured TiO2 and highly sensitive quartz resonators. The gas-sensing behavior of this new sensor to selected simulant warfare agents was
investigated at room temperature. Results showed rapid response and good reversibility of this sensor when used with high-purity
nitrogen. This provides a simple approach to preparation of materials needed as chemical sensors for selected organic volatiles
or warfare agents.
Figure Sensing behavior of TiO2 nanofiber sensor to chemical vapors 相似文献
6.
Webb A 《Analytical and bioanalytical chemistry》2007,388(3):525-528
Figure Schematic diagram of a typical arrangement used for hyphenating chemical microseparations (e.g. capillary HPLC, CE, or CEC)
with microcoil NMR detection 相似文献
7.
We screened a series of RNA and DNA aptamers for their ability to serve in the dye displacement assays in which analytes compete
with TO dye. We conclude that, while the performance of the TO dye displacement approach is not always predictable, it is
still a simple and sensitive assay to detect binding between RNA aptamers and small molecules. In particular, we describe
efficient assays for tobramycin and theophylline, with up to 90% displacement of TO observed, and we describe the first aptameric
assay for cAMP.
Figure An RNA or DNA aptamer against a molecule (circle) binds TO dye, resulting in a fluorescent complex. Presence of free molecule in solution results in the displacement of TO
from the complex and a reduction in fluorescence
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
8.
Losada J Zamora M García Armada P Cuadrado I Alonso B Casado CM 《Analytical and bioanalytical chemistry》2006,385(7):1209-1217
Amperometric bienzyme electrodes with horseradish peroxidase (HRP) and glucose oxidase (GOx) co-immobilized on polymethylferrocenyl
dendrimers deposited onto platinum electrodes have been used for determination of the hydrogen peroxide produced by the oxidase
during the enzymatic reaction. The redox dendrimers consist of flexible poly(propylenimine) dendrimer cores functionalised
with octamethylferrocenyl units. The effects of dendrimer generation, the thickness of the dendrimer layer, substrate concentration,
interferences, and reproducibility on the response of the sensors were investigated. The new bienzyme biosensors respond to
substrate at work potential values between 200 and 50 mV (vs. SCE), have good sensitivity, and are resistant to interferences.
Figure 相似文献
9.
Sensor technology and its application in environmental analysis 总被引:1,自引:0,他引:1
Environmental analysis is one of the fundamental applications of chemical sensors. In this review we describe different sensor
systems for the gas and liquid phases that have been tested either with real-life samples or in the field during the last
five years. Most field sensors rely either on electrochemical or optical transducers. In the gas phase, systems have been
proposed for analysis of oxides of nitrogen, carbon, and sulfur in air, and volatile organic compounds. In the liquid phase,
most detection systems used for real-life samples detect heavy-metal ions or organic contamination, for example pesticides,
organic solvents and polycyclic aromatic hydrocarbons.
Figure Chemical sensors for real-life environmental applications
Dedicated to Professor Ulrich Nickel on the occasion of his 65th birthday. 相似文献
10.
Schaffer B Grogger W Kothleitner G Hofer F 《Analytical and bioanalytical chemistry》2008,390(6):1439-1445
In this work we show how energy-filtered imaging can be used to obtain spectrum images of electron energy-loss spectrometric
data. Focus is placed on improved energy resolution within these data sets. Using two multilayer samples (GaN/AlN and InP/InAs),
we demonstrate the advantages of spectrum-imaging and its extended mapping capabilities. Plasmon-ratio maps are used to quickly
create high-contrast material maps with high signal-to-noise ratio, ratio-contrast plots are used to gain optimum settings
for the ratio maps, and plasmon-position maps are used to map small shifts of the energy position of bulk plasmon peaks.
Figure Scheme of EELS SI and derived plasman-position map 相似文献
11.
Kurt Kalcher Ivan Svancara Marijo Buzuk Karel Vytras Alain Walcarius 《Monatshefte für Chemie / Chemical Monthly》2009,140(8):861-889
Abstract An overview of the use of electrochemical sensors made from heterogeneous carbon materials (carbon paste electrodes, screen-printed
carbon electrodes) in the field of food analysis is presented. Sensors for inorganic and organic analytes as well as biosensors
are summarized.
Graphical abstract
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12.
Christine Mousty 《Analytical and bioanalytical chemistry》2010,396(1):315-325
Two-dimensional layered inorganic solids, such as cationic clays and layered double hydroxides (LDHs), also defined as anionic
clays, have open structures which are favourable for interactions with enzymes and which intercalate redox mediators. This
review aims to show the interest in clays and LDHs as suitable host matrices likely to immobilize enzymes onto electrode surfaces
for biosensing applications. It is meant to provide an overview of the various types of electrochemical biosensors that have
been developed with these 2D layered materials, along with significant advances over the last several years. The different
biosensor configurations and their specific transduction procedures are discussed.
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13.
Human immunoglobulin E (hIgE) is such an important protein, because of its involvement in allergic disease, that it is of
significance to study the interactions between it and its recognizing elements. In this report an analytical strategy based
on surface plasmon resonance (SPR) was developed to probe the pattern of interaction between hIgE and its recognizing molecules,
including aptamers and antibodies. The affinity constants of hIgE for the antibody and the aptamer were compared first; the
aptamer has more affinity than the antibody for human IgE. To study their pattern of interaction, three different binding
approaches, including adding the antibody and the streptavidin-coupled aptamer to the sensing surface, were designed. The
results showed that hIgE captured on the sensing surface could form a multivalent complex with the aptamer. An ELISA-like
assay using the aptamer as both capture and detection probes was then developed. This work highlights an SPR method for characterizing
the interaction between the protein and aptamers that is useful for study of biomolecular interaction patterns and binding
properties.
Figure Schematic diagram of the use of surface plasmon resonance for detection of the pattern of interaction of human IgE with its
DNA aptamer and antibody 相似文献
14.
An aptamer-based label-free approach to hemin recognition and DNA assay using capillary electrophoresis with chemiluminescence
detection is introduced here. Two guanine-rich DNA aptamers were used as the recognition element and target DNA, respectively.
In the presence of potassium ions, the two aptamers folded into the G-quartet structures, binding hemin with high specificity
and affinity. Based on the G-quartet–hemin interactions, the ligand molecule was specifically recognized with a K
d ≈ 73 nM, and the target DNA could be detected at 0.1 μM. In phosphate buffer of pH 11.0, hemin catalyzed the H2O2-mediated oxidation of luminol to generate strong chemiluminescence signal; thus the target molecule itself served as an indicator
for the molecule–aptamer interaction, which made the labeling and/or modification of aptamers or target molecules unnecessary.
This label-free method for molecular recognition and DNA detection is therefore simple, easy, and effective.
Figure A label-free approach to aptamer-based hemin recognition and DNA detection is introduced, which gives great potential for
using a small molecule itself as the indicator for molecular recognition and DNA detection thereby avoiding any labeling or
modification step 相似文献
15.
Cordes DB Miller A Gamsey S Singaram B 《Analytical and bioanalytical chemistry》2007,387(8):2767-2773
The simultaneous use of several fluorescent reporter dyes in a multicomponent boronic acid-based glucose sensing system is
reported. In one application, two dyes with widely different emission wavelengths are used to report changes in glucose concentration.
A third glucose-insensitive dye was then added to act as a reference dye and provide for a ratiometric correction to the two
reporter dye signals. The inclusion of such a reference dye reduces errors arising from sources such as fluctuations in lamp
intensity and sample dilution.
The simultaneous use of multiple fluorescent reporter dyes 相似文献
16.
Willard DM Mutschler T Yu M Jung J Van Orden A 《Analytical and bioanalytical chemistry》2006,384(3):564-571
Nanoscale sensors can be created when an expected energetic pathway is created and then that pathway is either initiated or
disrupted by a specific binding event. Constructing the sensor on the nanoscale could lead to greater sensitivity and lower
limits of detection. To this end, quantum dots (QDs) can be considered prime candidates for the active components. Relative
to organic chromophores, QDs have tunable spectral properties, show less susceptibility to photobleaching, have similar brightness,
and have been shown to display electro-optical properties. In this review, we discuss recent articles that incorporate QDs
into directed energy flow systems, some with the goal of building new and more powerful sensors and others that could lead
to more powerful sensors.
Figure 相似文献
17.
Wang Z Wilkop T Xu D Dong Y Ma G Cheng Q 《Analytical and bioanalytical chemistry》2007,389(3):819-825
We report on the use of PDMS multichannels for affinity studies of DNA aptamer–human Immunoglobulin E (IgE) interactions by
surface plasmon resonance imaging (SPRi). The sensing surface was prepared with thiol-terminated aptamers through a self-assembling
process in the PDMS channels defined on a gold substrate. Cysteamine was codeposited with the thiol aptamers to promote proper
spatial arrangement of the aptamers and thus maintain their optimal binding efficiencies. Four aptamers with different nucleic
acid sequences were studied to test their interaction affinity toward IgE, and the results confirmed that aptamer I (5′-SH-GGG
GCA CGT TTA TCC GTC CCT CCT AGT GGC GTG CCC C-3′) has the strongest binding affinity. Control experiments were conducted with
a PEG-functionalized surface and IgG was used to replace IgE in order to verify the selective binding of aptamer I to the
IgE molecules. A linear concentration-dependent relationship between IgE and aptamer I was obtained, and a 2-nM detection
limit was achieved. SPRi data were further analyzed by global fitting, and the dissociation constant of aptamer I–IgE complex
was found to be 2.7 × 10−7 M, which agrees relatively well with the values reported in the literature. Aptamer affinity screening by SPR imaging demonstrates
marked advantages over competing methods because it does not require labeling, can be used in real-time, and is potentially
high-throughput. The ability to provide both qualitative and quantitative results on a multichannel chip further establishes
SPRi as a powerful tool for the study of biological interactions in a multiplexed format.
Figure The SPRi sensograms and thier global fits for aptamer I and IgE interactions. Insert in the difference image obtained with
the PDMS microchannel flow cell for aptamer IV, III, and I (from left to right 相似文献
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20.
Ortner K Sivanandam VN Buchberger W Müller N 《Analytical and bioanalytical chemistry》2007,388(1):173-177
Enzymatically cleaved glycans from sub-milligram quantities of erythropoietin (EPO) and ovalbumin have been analyzed, without
further purification, by two-dimensional diffusion-ordered nuclear magnetic resonance spectroscopy. At NMR sample concentrations
below 50 μmol L−1 the major components of the oligosaccharide fractions could be distinguished by their anomeric proton chemical shift and
their size-dependent diffusion coefficients.
Figure
1H NMR diffusion decay curves of anomeric protons in the EPO glycan fraction 相似文献